Abstract: A method and a device determine the heating state of an optical element in an optical system, for example in a microlithographic projection exposure system. Electromagnetic radiation hits an incidence surface of the optical element during operation of the optical system. Using a calibration parameter, an average temperature at the incidence surface is estimated on the basis of a temperature measurement carried out via at least one temperature sensor located a distance from the incidence surface. The calibration parameter is selected differently in accordance with the illumination setting which is set in the optical system.

Abstract: An optical assembly has an optical element for influencing the beam path in a projection exposure apparatus and an actuator device for deforming the optical element. The actuator device has at least one photostrictive component and at least one light source. The photostrictive component is mechanically coupled to the optical element for the transmission of a tensile and/or compressive force in order to deform the optical element. The light source is configured for targeted illumination of the photostrictive component in order to induce the tensile and/or compressive force in the photostrictive component.

Abstract: A method for heating an optical element in an optical system, such as a microlithographic projection exposure system, comprises introducing a heating power into the optical element using a thermal manipulator. The heating power is adjusted to a set of desired values. The set of desired values is adjusted to produce a thermally induced deformation depending on a first optical aberration to be compensated. Adjusting the set of desired values also includes taking into account the effect of introducing the heating power on a second optical aberration which is caused by useful light impinging on the optical element during operation of the optical system. The thermally induced deformation profile can be co-optimized.

Abstract: An optical assembly has an optical element for influencing the beam path in a projection exposure apparatus and an actuator device for deforming the optical element. The actuator device has at least one photostrictive component and at least one light source. The photostrictive component is mechanically coupled to the optical element for the transmission of a tensile and/or compressive force in order to deform the optical element. The light source is configured for targeted illumination of the photostrictive component in order to induce the tensile and/or compressive force in the photostrictive component.

Abstract: A method and a device determine the heating state of an optical element in an optical system, for example in a microlithographic projection exposure system. Electromagnetic radiation hits an incidence surface of the optical element during operation of the optical system. Using a calibration parameter, an average temperature at the incidence surface is estimated on the basis of a temperature measurement carried out via at least one temperature sensor located a distance from the incidence surface. The calibration parameter is selected differently in accordance with the illumination setting which is set in the optical system.

Abstract: Aberrations of a projection lens for microlithography can be subdivided into two classes: a first class of aberrations, which are distinguished by virtue of the fact that their future size increases by a non-negligible value after a constant time duration, independently of their current size, and a second class of aberrations, which, after reaching a threshold, only increase by a negligible value after each further time duration. An adjustment method is proposed, which adjusts these two classes of aberrations in parallel in time with one another.

Abstract: Aberrations of a projection lens for microlithography can be subdivided into two classes: a first class of aberrations, which are distinguished by virtue of the fact that their future size increases by a non-negligible value after a constant time duration, independently of their current size, and a second class of aberrations, which, after reaching a threshold, only increase by a negligible value after each further time duration. An adjustment method is proposed, which adjusts these two classes of aberrations in parallel in time with one another.